This invention relates to a substrate conveying system, a substrate conveying method and/or a substrate conveying hand mechanism, for conveying a substrate such as a semiconductor wafer, for example. In another aspect, the invention is concerned with a semiconductor manufacturing apparatus having an arrangement for performing an ashing process by use of such a substrate conveying system, or a semiconductor device manufacturing method including an ashing process by use of such a substrate conveying system.
In some semiconductor manufacturing apparatuses, for processing substrates such as semiconductor wafers or glass substrates, for example, the substrates are sequentially and circulatively conveyed to various processing units so that various processes such as surface treatment, for example, are performed to the substrates in these units.
As a substrate conveying mechanism used in such circulation conveyance type substrate conveying systems, there are a sequential conveyance type robot for conveying each substrate while gripping the same and a double-hand type robot having a two-level hand structure with upper and lower substrate holding portions. With this double-hand type conveying mechanism, each processing unit can be accessed by two hands sequentially, such that, in each processing unit, high-speed processing can be done while interchanging substrates such as wafers.
Generally, a substrate conveying system has a substrate holding means provided at a free end of a robot arm. The robot arm can be moved rotationally, extended or contracted horizontally and moved vertically, to perform transfer of a substrate between it and a processing unit. Also, there are cases wherein the robot itself is made rotationally movable and also movable horizontally or vertically.
These motions are controlled in accordance with axes (drive axes) corresponding to the motions, respectively. Namely, there are an axis for rotational motion, an axis for horizontal motion and an axis for vertical motion, for example.
As regards operation commands to such a conveyance robot, generally, a distance from a mechanical origin is taught to each axis defined in the robot in the form of a coordinate value (teaching position). Each value is stored in a memory of the robot. A host controller then specifies, with reference to the thus stored positions, a substrate transfer operation or any other independent operations related to respective axes.
In conventional conveying systems such as described above, only a single operation speed is set with respect to each driving axis of the robot. As a result, when the;conveyance robot conveys a substrate into a processing unit, a high-speed collision may occur between the substrate and the processing unit. The impact of collision may cause vibration of the substrate in the processing unit, as the same is loaded into the processing unit, and accurate processing may be interrupted. On the other hand, when the conveyance robot takes the substrate out of the processing unit, there may occur a high-speed collision between the substrate and the conveyance robot. The impact of collision may disturb accurate conveyance.
Recently, the wafer size becomes larger and thus the wafer weight becomes heavier. This makes the impact of collision between a substrate and a processing unit or between a substrate and a conveyance robot quite larger, and the influence thereof becomes critical.
On the other hand, conventional substrate conveying robot systems use substrate holding methods such as of a vacuum finger type wherein a substrate is attracted by vacuum, a fit-in type wherein a substrate is fitted in a recessed portion and held thereby, or a mechanical grip type (Japanese Laid-Open Patent Application, Laid-Open No. 22502/1995) wherein a free-end side gripping portion is moved toward an arm grip of arcuate shape so that a substrate is sandwiched between them.
However, these conventional substrate holding methods involve problems of contamination or deformation of a substrate, for example. While details will be discussed later in this specification (specifically, in relation to a third embodiment), there is a possibility that particles produced at a mechanical sliding portion of a conveyance robot or a friction portion between a substrate and a substrate holding element of the conveyance robot are adhered to the substrate, to cause contamination of the same. Also, there is a possibility that a temperature difference is created between a top face side of a substrate and a bottom face side thereof as held by a robot arm of the conveyance robot, which may cause warp of the substrate or a crack in the substrate.
It is accordingly an object of the present invention to provide a substrate conveying system and/or a substrate conveying method, by which high-speed collision of a substrate during transportation of the substrate by a conveyance robot or the like can be avoided.
It is another object of the present invention to provide a substrate conveying hand mechanism by which contamination of a substrate by particles and/or deformation of the substrate due to a temperature difference can be avoided.
In accordance with an aspect of the present invention, there is provided a substrate conveying system, comprising: a robot arm with substrate holding means for holding a substrate, said robot arm being operable to move said substrate holding means to a predetermined position to enable transfer of the substrate; and control means for controlling movement of said substrate holding means to said predetermined position, said control means having at least one axis and being operable to control the movement of said substrate holding means related to said at least one axis, with respect to at least four, first to fourth, positions, wherein the first position is a movement start position where the movement of said substrate holding means is to be started, wherein the second position is a first speed changing position where a movement speed of said substrate holding means is to be changed from a first set speed to a second set speed, wherein the third position is a second speed changing position where the movement speed of said substrate holding means is to be changed from the second set speed to the first set speed, and wherein the fourth position is a movement completion position where the movement of said substrate holding means is to be completed.
The transfer of the substrate may be performed during movement of said substrate holding means from the first speed changing position to the second speed changing position.
The second set speed may be slower than the first set speed.
The substrate holding means may include a holding mechanism for mechanically holding the substrate.
In accordance with another aspect of the present invention, there is provided a substrate conveying method, comprising the steps of: holding a substrate through a substrate holding device provided on a robot arm; and moving the substrate holding device to a predetermined position in accordance with at least one axis, for transfer of the substrate; wherein said moving step for moving the substrate holding means device in accordance with the at least one axis includes (i) moving, at a first set speed, the substrate holding device to a movement start position where the movement of the substrate holding device is to be started, (ii) moving, at the first set speed, the substrate holding device to a first speed changing position where a movement speed of the substrate holding device is to be changed from the first set speed to a second set speed, (iii) moving, at the second set speed, the substrate holding device to a second speed changing position where the movement speed of the substrate holding device is to be changed from the second set speed to the first set speed, and (iv) moving, at the first set speed, the substrate holding device to a movement completion position where the movement of the substrate holding device is to be completed.
The transfer of the substrate may be performed during movement, at the second set speed, of the substrate holding device from the first speed changing position to the second speed changing position.
The second set speed may be slower than the first set speed.
The substrate holding device may include a holding mechanism for mechanically holding the substrate.
In accordance with a further aspect of the present invention, there is provided a substrate conveying system, comprising: a robot arm with substrate holding means for holding a substrate, said robot arm being operable to move said substrate holding means to a predetermined position to enable transfer of the substrate; and control means for controlling movement of said substrate holding means to said predetermined position, said control means having at least two axes and being operable to control the movement of said substrate holding means related to said at least two axes, with respect to at least seven, first to seventh, positions, wherein the first position is a movement start position for a first axis where the movement of said substrate holding means with respect to the first axis is to be started, wherein the second position is a movement start position for a second axis where the movement of said substrate holding means with respect to the second axis is to be started, wherein the third position is a first speed changing position for the second axis where a movement speed of said substrate holding means with respect to the second axis is to be changed from a first set speed for the second axis to a second set speed for the second axis, wherein the fourth position is a second speed changing position for the second axis where the movement speed of said substrate holding means with respect to the second axis is to be changed from the second set speed for the second axis to the first set speed for the second axis, wherein the fifth position is a second speed changing position for the first axis where the movement speed of said substrate holding means with respect to the first axis is to be changed from a second set speed for the first axis to a first set speed for the first axis, wherein the sixth position is a movement completion position for the first axis where the movement of said substrate holding means with respect to the first axis is to be completed, and wherein the seventh position is a movement completion position for the second axis where the movement of said substrate holding means with respect to the second axis is to be completed.
The transfer of the substrate may be performed during movement of said substrate holding means from the first speed changing position for the second axis to the second speed changing position for the second axis.
The second set speed for the second axis may be slower than the first set speed for the second axis, and the second set speed for the first axis may be slower than the first set speed for the first axis.
The substrate holding means may include a holding mechanism for mechanically holding the substrate.
In accordance with a yet further aspect of the present invention, there is provided a substrate conveying method, comprising the steps of: holding a substrate through a substrate holding device provided on a robot arm; and moving the substrate holding device to a predetermined position in accordance with at least two axes, to enable transfer of the substrate; wherein said moving step for moving the substrate holding device in accordance with at least two axes includes (i) moving, at a first set speed with respect to a first axis and also at a first set speed with respect to a second axis, the substrate holding device to a movement start position for the first axis where the movement of the substrate holding device with respect to the first axis is to be started, (ii) moving, at the first set speed with respect to the first axis, the substrate holding device to a movement start position for the second axis where the movement of the substrate holding device with respect to the second axis is to be started, (iii) moving, at the first set speed with respect to the second axis, the substrate holding device to a first speed changing position for the second axis where a movement speed of the substrate holding device is to be changed from the first set speed for the second axis to a second set speed for the second axis, (iv) moving, at the second set speed with respect to the second axis, the substrate holding device to a second speed changing position for the second axis where the movement speed of the substrate holding device is to be changed from the second set speed for the second axis to the first set speed for the second axis, (v) moving, at the first set speed with respect to the second axis, the substrate holding device to a movement completion position for the second axis where the movement of the substrate holding device with respect to the second axis is to be completed, (vi) moving, at the second set speed with respect to the first axis, the substrate holding device to a second speed changing position for the first axis where the movement speed of the substrate holding device is to be changed from a second set speed for the first axis to the first set speed for the first axis, and (vii) moving, at the first set speed with respect to the first axis, the substrate holding device to a movement completion position for the first axis where the movement of the substrate holding means with respect to the first axis is to be completed.
The transfer of the substrate may be performed during movement, at the second set speed with respect to the second axis, of the substrate holding device from the first speed changing position for the second axis to the second speed changing position for the second axis.
The second set speed for the second axis may be slower than the first set speed for the second axis, and the second set speed for the first axis may be slower than the first set speed for the first axis.
The substrate holding device may include a holding mechanism for mechanically holding the substrate.
In accordance with a yet further aspect of the present invention, there is provided a substrate conveying hand mechanism, comprising: fixed pawls provided at least at two locations; at least one movable pawl movably disposed with a variable distance to said fixed pawls, for sandwiching and holding a substrate between the same and said fixed pawls; and bellows means connected to said at least one movable pawl and being able to be expanded and contracted through actuation of a fluid, to change the distance between said at least one movable pawl and said fixed pawls.
The at least one movable pawl may include a pair of parallel arms each being swingably supported, and a tension spring for applying a tension urging force between said parallel arms, wherein a substrate can be held between said parallel arms as they are opened against the tension spring.
The at least one movable pawl may include an engagement adapted to be in roll engagement with a substrate when the same is held.
The substrate conveying system may further comprise an opening formed in a face to be opposed to the substrate, for releasing heat from the substrate as the same is held.
In accordance with a still further aspect of the present invention, there is provided a substrate conveying method, comprising the steps of: holding a substrate through a substrate holding device provided on a robot arm; and moving the substrate holding device in accordance with at least one axis, to a predetermined position, for transfer of the substrate; wherein said substrate holding device satisfies a relation with respect to said at least one axis that a position of said substrate holding device for receiving the substrate differs from a position of said substrate holding device for sending the substrate therefrom.
In accordance with a yet further aspect of the present invention, there is provided a semiconductor manufacturing apparatus including a substrate conveying system such as described above.
In accordance with a yet further aspect of the present invention, there is provided a semiconductor manufacturing apparatus including a substrate conveying hand mechanism as recited above.
In accordance with a still further aspect of the present invention, there is provided a semiconductor device manufacturing method including a step for processing a substrate conveyed in accordance with a substrate conveying method as recited above.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.